What type of boiler do I have?

If you haven’t lived in your property long or you have never had to replace your heating system, we can appreciate that you may not be familiar with the type of boiler that you have. The type of boiler you have is probably one of the following:

  • Combi boiler 
  • Regular boiler
  • System boiler

Types of boiler refers to the above and not the fuel source that your boiler uses. In regard to fuel source, your boiler will most likely utilise gas, oil, or LPG. 

It should be easier for you to determine which fuel your boiler runs as you will either regularly receive a gas bill, or you will have an oil or LPG tank to the exterior of your property and will be charged for the filling of this. 

When it comes to boiler type, there are clear distinctions about how each type works and the property that they are most suited to. To assist you in understanding what type of boiler you currently have and the replacement you will require, we have put together the following guide.

Looking for a replacement boiler?
types of boiler

Identifying your boiler 

The easiest way to identify the type of boiler you currently have is to look at the heating system components installed in your home. 

  • Do you have a hot water cylinder in your airing cupboard?
  • Do you have a cold water storage tank in your loft?
  • Do you have an external pump?

What boiler do I have? – At a glance

Our at a glance table will quickly tell you the most likely boiler you currently have installed in your home based on the above questions. 

Hot water cylinder in your airing cupboardCold water storage tank in your loftAn external pumpMost likely boiler
NoNoNoCombi boiler
YesNoNoSystem boiler
YesYesYesRegular boiler

How do I know if I have a combi boiler?

Combi boiler

If your answer to all of the above questions is no, then your current boiler is almost certainly a combi boiler.

You won’t have a hot water cylinder or a cold water storage tank, as all of the components for central heating and hot water are housed in the combi boiler unit itself.

It should be noted that you may still have these components and have a combi boiler installed, in this case, you should check whether they are still being utilised as a part of your heating system. It may be that they have been leftover from a previous installation but are no longer in use.

If you are unable to check whether or not you have these external components, another way of checking is to look at the pipes coming out of the boiler. 

Are there 5 copper pipes coming out of the boiler? If yes, then it is likely that you have a combi boiler. 

Your property type may also be able to help you identify whether you have a combi boiler. These are most often installed in smaller properties with only one bathroom, as they only allow hot water to be delivered to one shower or tap at a time.  

In a combi boiler installation, your cold water will be provided from the mains supply and your hot water will be heated from the boiler, and only provided when you need it.

Combi boilers are now the most common type of boiler installed in the UK.

Looking for a replacement combi boiler?

How do I know if I have a system boiler?

System boiler

You almost certainly have a system boiler if you have answered yes to having a hot water cylinder but no to having a cold water storage tank and an external pump. You should of course check that the hot water cylinder is still being used and hasn’t just been left over.

Another way of checking if you have a system boiler is to look at the number of pipes coming out of the boiler. 

Are there 3 copper pipes coming out of the boiler? If yes, then it is likely that you have a system boiler. 

In a system boiler installation, you won’t get instant hot water as you do with a combi boiler. This will instead be provided from the hot water cylinder, which is usually found in the airing cupboard. 

System boilers are usually installed in larger properties with multiple bathrooms as they allow hot water to be delivered to multiple showers and taps at the same time.

Looking for a replacement system boiler?

How do I know if I have a regular boiler?

Regular boiler

If you have answered yes to having a hot water cylinder, a cold water storage tank, and an external pump, then it’s likely that you have a regular boiler (sometimes also called conventional or open vent boilers). Like with the other boiler types, you should check that all of the components of your heating system are still being used to provide your home with heating and hot water.

Another way to check is to look at the pipes coming out of the top and the bottom of your boiler. Regular boilers will usually have two pipes coming out of the top of the boiler unit and one coming out of the bottom.

Regular boilers take up the most space out of the boiler systems we have detailed here but have the ability to supply hot water across several bathrooms, meaning that they are most often installed in larger homes. 

Looking for a replacement regular boiler?

How do I know if I have a back boiler?

If you have a boiler fitted behind your fireplace, then this is a back boiler. Installed from the 1960s to the 1980s, back boilers are space-saving boilers that provide central heating and hot water to homes. However, due to being inefficient and in some cases, dangerous, back boilers are no longer installed. In place of a back boiler, we recommend the installation of a combi boiler.

The most common back boilers installed in the UK were the Baxi Bermuda.

Looking for a replacement for your back boiler?

Still unsure?

If you are still unsure and you have the make and model of your current boiler to hand, a quick search online will tell you what type of boiler it is. If this doesn’t help you, we can. Contact us or call us on 02920 099898 with the details of your boiler and we will identify what it is, and what we recommend to replace it.

Frequently Asked Questions

Combi boilers currently available in the UK include:

Ariston Alteas ONE Net
Ariston Clas ONE
Ariston E-Combi ONE
Ariston Genus ONE Net
Baxi 200
Baxi 400
Baxi 600
Baxi 800
Baxi Duo-tec
Baxi Platinum
Glow-worm Betacom₄
Glow-worm Easicom₃
Glow-worm Energy
Glow-worm Energy 35 Store
Glow-worm Essential
Glow-worm Ultimate₃
Grant Vortex Blue
Grant Vortex Pro
Ideal Logic Max
Ideal Logic+
Ideal Vogue
Ideal Vogue Max
Navien Condensing NCB
Navien LCB700 Blue Flame
Vaillant ecoFIT pure
Vaillant ecoTEC exclusive with Green iQ
Vaillant ecoTEC plus Combination Store
Vaillant ecoTEC Pro Combi
Viessmann Vitodens 050-W
Viessmann Vitodens 100-W
Viessmann Vitodens 111-W
Worcester Bosch Greenstar 2000
Worcester Bosch Greenstar 8000
Worcester Bosch Greenstar 8000 Life
Worcester Bosch Greenstar 8000 Style
Worcester Bosch Greenstar CDi Compact
Worcester Bosch Greenstar CDi Highflow
Worcester Bosch Greenstar Heatslave II
Worcester Bosch Greenstar i
Worcester Bosch Greenstar Si Compact

System boilers currently available in the UK include:

Ariston Clas System ONE
Ariston E-System ONE
Baxi 600
Baxi 800
Baxi Megaflo
Baxi Platinum+
Glow-worm Easicom₃
Glow-worm Energy
Glow-worm Ultimate₃
Grant Vortex Eco
Ideal Logic Max
Ideal Logic+
Ideal Vogue
Ideal Vogue Max
Vaillant ecoFIT pure
Vaillant ecoTEC exclusive with Green iQ
Vaillant ecoTEC plus
Viessmann Vitodens 100-W
Viessmann Vitodens 200-W
Worcester Bosch GB162
Worcester Bosch Greenstar 8000 Life
Worcester Bosch Greenstar Danesmoor
Worcester Bosch Greenstar i
Worcester Greenstar 8000 Style

Regular boilers currently available in the UK include:

Baxi 400
Baxi 600
Baxi 800
Glow-worm Easicom₃
Glow-worm Energy
Glow-worm Ultimate₃
Grant Vortex Eco
Grant Vortex Pro
Ideal Logic Max
Ideal Logic+
Ideal Mexico HE
Vaillant ecoFIT pure
Vaillant ecoTEC plus
Viessmann Vitodens 100-W Open Vent
Viessmann Vitodens 200-W
Worcester Bosch Greenstar 8000 Life Regular
Worcester Bosch Greenstar CDi FS Regular
Worcester Bosch Greenstar Danesmoor
Worcester Bosch Greenstar Ri
Worcester Bosch Utility Regular